It is well known to produce hydrogen cyanide particularly by the Andrussow process, U.S. Pat. No. 1,934,838, which involves essentially reaction of methane with ammonia and air over a platinum metal catalyst at an elevated temperature (about 1000.degree.C.). In this process a mixture of products is obtained including the desired hydrogen cyanide as well as water, unreacted ammonia and methane, nitrogen, argon, hydrogen and oxides of carbon. An improvement to the Andrussow process wherein the reactants prior to reaction are mixed with steam is described in U.S. Pat. No. 3,667,907.
Such a product mixture serves as a widely used source of hydrogen cyanide especially where the hydrogen cyanide can be utilized in the form of an alkaline solution such as that of an alkali or alkaline earth metal.
For purposes wherein substantially anhydrous hydrogen cyanide is required, complicated and expensive rectification and isolation procedures have been necessary to provide a satisfactory product. Also, the more efficient utilization of hydrogen cyanide in the production of cyanohydrins such as acetone cyanohydrin, which is an important intermediate in the manufacture of methacrylate resins, has continued to be a major research objective. Accordingly, improved methods have been sought for utilizing hydrogen cyanide contained in gaseous mixtures in the preparation of ketone cyanohydrins and for providing hydrogen cyanide in substantially anhydrous form.